Corundum crystal recording or reproducing member



Aug. 14, 1951 c. c. VERHEYEN ,564,

CORUNDUM CRYSTAL RECORDING OR REPRODUCING MEMBER I Filed July 2, 1946 INVENTOR. VERHEYEN COENRAAD C.

AGENT Patented Aug. 14, 1951 CORUNDUM CRYSTAL RECORDING OR REPRODUCIN G MEMBER Coenraad Cornelis Verheyen, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application July 2, 1946, Serial No. 680,910 In the Netherlands March 4, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires March 4, 1963 3 Claims.

The invention relates generally to cutting members for mechanically recording or reproducing records, such as phonograph records, for example, and more particularly to those members, which consists of a crystal.

In recording sound with the aid of such a cutting member which is made, for example, of corundum crystal and which has a V-shaped cutting edge, there arises the drawback that the cutting edges wear off very soon or that small pieces of crystal break off therefrom, with the result that, for example, sound tracks recorded with the aid of such a member have, during reproduction, a kind of fading effect with distortion. As regards members with the aid of which, for example, mechanically provided sound tracks are reproduced, the above-mentioned drawback results in that the oscillation tracks wear off or are damaged more rapidly than usual.

With the member according to the invention, this drawback is avoided due to the fact that the longitudinal axis of the member and the principal axis of the crystal are perpendicular to one another, which may be achieved by a properly chosen method of grinding. It has been found achieve that the axis B-B will be perpendicular to the axis AA.

Fig. 4 represents part of a phonograph needle wherein B-B also represents the longitudinal axis.

What I claim is:

1. A member for mechanically recording or reproducing phonograph records comprising a uniaxial corundum crystal, said member having the longitudinal axis thereof perpendicular to the principal axis of said crystal said member having a pair of side surfaces each substantially parallel to said longitudinal axis and another pair of surfaces at one end thereof each extending from one of said side surfaces, respectively, at a substantial angle to said longitudinal axis and intersecting with each other to form a substantially sharp edge at said one end thereof.

2. A member for mechanically recording or reproducing phonograph records comprising a crystal having only one principal axis, said member having the longitudinal axis thereof perpendicular to said principal axis of said crystal, said member having a pair of side surfaces each substantially parallel to said longitudinal axis and another surface at one end thereof extending from one of said side surfaces at a substantial angle to said longitudinal axis and terminating to form a substantially sharp edge at said one end thereof.

3. A member for mechanically recording or reproducing phonograph records comprising a crystal having only one principal axis, said member having the longitudinal axis thereof perpendicular to said principal axis of said crystal, said member having a pair of side surfaces each substantially parallel to said longitudinal axis and another pair of surfaces at one end thereof each extending from one of said side surfaces, respectively, at a substantial angle to said longitudinal axis and intersecting with each other to form a substantially sharp edge at said one end thereof.

COENRAAD CORNELIS V'ERHEYEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 484,583 Edison Oct. 18, 1922 1,737,253 Linsell Nov. 26, 1929 2,355,877 Le Van l Aug. 15, 1944 FOREIGN PATENTS Number Country Date 402,575 France Oct. 12, 1902 728,644 France Apr. 18, 1932 751,047 France June 12; 1933 

